PATCH to stl_iterator.h to make `iterator' usable

[Jason Merrill]

>>>>> Mark Mitchell <mark@codesourcery.com> writes:

 > I think this is probably #ifdef'd out because it conflicts with two
 > many programs that use the identifier `iterator' in some other way.

Perhaps.  The folks at SGI would know better...

 > So, I don't think we should apply your patch.  Jason might feel
 > differently, of course.

I don't feel strongly about it.  My inclination would be to apply it and
see what breaks.

Jason